The present invention relates to a wavelength switching light source for use in optical communication systems and the like, and more particularly to a wavelength switching light source capable of high-speed switching of the wavelength of output light.
Known examples of optical communication system requiring high-speed switching of the wavelength of output light include, for instance, the optical packet transfer network described in "Wavelength-addressed optical network using an ATM cell-based access scheme" (by N. Shimosaka et al. ), Conference on Optical Fiber Communication/International Conference on Integrated Optics and Optical Fiber Communication, Technical Digest Series, Volume 4 (1993), pp. 49-50.
In this system, the wavelength of the light source should be switched and the altered wavelength should be stabilized within the guard time left between consecutive packets. To meet this need, the arrangement described in this literature uses a variable-wavelength light source consisting of two semiconductor lasers and an optical switch for selectively supplying the output light of one or the other of the two semiconductor lasers.
Incidentally, whereas the oscillation wavelength of a semiconductor laser varies with temperature fluctuations and accordingly these temperature fluctuations should be compensated for, the variable-wavelength light source described in this literature requires either a temperature compensation circuit for each semiconductor laser or a constant temperature device accommodating a plurality of semiconductor lasers, and entails the problem that the dimensions of the variable-wavelength light source would increase with the number of wavelengths used.